CVE-2021-1240 in Proximity Desktop
Summary
by MITRE • 01/14/2021
A vulnerability in the loading process of specific DLLs in Cisco Proximity Desktop for Windows could allow an authenticated, local attacker to load a malicious library. To exploit this vulnerability, the attacker must have valid credentials on the Windows system. This vulnerability is due to incorrect handling of directory paths at run time. An attacker could exploit this vulnerability by placing a malicious DLL file in a specific location on the targeted system. This file will execute when the vulnerable application launches. A successful exploit could allow the attacker to execute arbitrary code on the targeted system with the privileges of another user’s account.
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Analysis
by VulDB Data Team • 02/14/2021
The vulnerability identified as CVE-2021-1240 resides within Cisco Proximity Desktop for Windows, a desktop application designed for proximity-based services and location tracking. This security flaw represents a classic case of insecure library loading that stems from improper handling of dynamic link library (DLL) path resolution during application execution. The vulnerability specifically manifests when the application attempts to load certain DLL files, creating an opportunity for privilege escalation through malicious code injection. The attack vector requires local system access with valid user credentials, making it an authenticated local privilege escalation vulnerability that operates within the confines of legitimate user sessions.
The technical root cause of this vulnerability lies in the application's failure to properly validate and sanitize directory paths during the DLL loading process. This weakness aligns with CWE-770, which addresses the improper handling of resource loading operations, and specifically relates to CWE-427, which covers uncontrolled search path elements. The application's runtime behavior demonstrates a lack of proper path validation that allows attackers to manipulate the DLL search order, enabling them to inject malicious code through carefully placed DLL files in predetermined locations. This flaw operates under the principle that the system will load the first DLL it finds in the search path, regardless of its legitimacy or origin, creating a dangerous window of opportunity for exploitation.
The operational impact of this vulnerability extends beyond simple code execution, as it enables authenticated attackers to escalate privileges and potentially gain access to other user accounts with elevated permissions. When an attacker successfully places a malicious DLL in the targeted location, the vulnerable application will execute this code during its normal startup process, effectively providing the attacker with a persistent foothold on the compromised system. This vulnerability directly maps to the ATT&CK technique T1068, which describes the use of local privilege escalation to gain elevated system access. The implications are particularly concerning because the attacker can execute code with the privileges of another user's account, potentially enabling lateral movement within the network and access to sensitive resources that would otherwise be protected by standard user permissions.
Mitigation strategies for CVE-2021-1240 should focus on both immediate remediation and long-term architectural improvements. Cisco has released patches and updates to address this vulnerability, which should be deployed immediately across all affected systems. System administrators should implement proper access controls and privilege management to limit the potential impact of successful exploitation attempts. The use of application whitelisting and strict path validation mechanisms can help prevent unauthorized DLL loading operations. Additionally, implementing the principle of least privilege and regular security audits of system directories can reduce the attack surface. Organizations should also consider deploying endpoint protection solutions that monitor for suspicious DLL loading activities and maintain comprehensive logging of application execution events to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper DLL loading practices and highlights the necessity of following secure coding guidelines that address dynamic library loading vulnerabilities.